<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>demo3</title>
    <style>
        .border-test{
            /* border: red solid 10px; */
            border-color: red;
            border-width: 2px 5px 8px 15px;/*上右下左的顺序*/
            /* border-top-width: 2px;
            border-bottom-width: 8px;
            border-left-width: 15px;
            border-right-width: 5px; */
            border-style: solid;
            /* 同理都可以分别设置四条边框 */
        }
        .width-height-test{
            border: solid black 1px;
            width: 200px;
            height: 200px;
        }
    </style>
</head>
<body>
    <div>
        <span class="border-test">111</span>
        <span class="border-test">222</span>
        <span class="border-test">333</span>
    </div>
    <br>
    <br>
    <br>
    <br>
    <br>
    <div class="width-height-test"><!-- width和height只针对块级元素生效 -->
        <span class="width-height-test">111</span>
        <span class="width-height-test">222</span>
        <span class="width-height-test">333</span> <!-- width和height对行内元素无效 -->
    </div>
</body>
</html>